The present invention relates to a sheet finisher which conducts post processing such as stapling processing, folding processing, or similar processing on sheets on which images are recorded by an image forming apparatus such as a copier, printer, facsimile device, or hybrid machine including these apparatus, and to an image forming apparatus having the sheet finisher.
Conventionally, the following technology is well known as a sheet finisher which conducts edge stapling processing, or center stapling processing on a set of sheets which is formed such that a plurality of sheets on which images are recorded by an image forming apparatus such as a copier, or printer, are bundled to one set.
The technology disclosed in Japanese Tokkaisho No. 61-139495 is a sheet finisher in which a stapler for edge stapling and s stapler for center stapling are separately arranged.
The technology disclosed in Japanese Tokkaihei No. 2-144370 is a sheet finisher in which the following operations are conducted: when the center stapling processing is conducted, delivered sheet is switch-backed and conveyed to the center stapling position; and the trailing edge of the sheet is put in order on the reference surface and stacked, and then center stapling is conducted.
A sheet finisher which is composed of total 3 sets of staplers, that is, 2 sets of staplers for edge stapling processing for 2 portions in the vicinity of the sheet side edge and for center stapling processing for 2 portions in the central portion of the sheet, and further a slant stapling only stapler for slant edge stapling processing for one portion in the vicinity of the corner portion of the sheet, is conventionally known.
The following problems exist in the conventional technology.
(a) Because the edge stapling stapler and center stapling stapler are separately provided, the size of the overall sheet finisher is increased. Further, the production cost is increased.
(b) The distance to convey the sheet to the central stapling position is increased, and therefore, at the time of center stapling processing, a time period for the sheet arrangement is longer, thereby, the productivity for the sheet processing is lowered.
(c) Because 2 sets of staplers for the edge stapling processing and for the center stapling processing, and further a slant stapling only stapler for slant edge stapling processing are provided, and in order to prevent the interference between the slant stapling only stapler and the other 2 sets of staplers, the stapler driving mechanism becomes complicated. Further, total 3 sets of staplers are necessary, resulting in high production cost.
Further, a finisher as the sheet finisher is already disclosed in Japanese Tokkaisho No. 60-142359, No. 60-185463, No. 62-239169, further, Japanese Tokkaisho No. 62-288002, No. 63-267667, Japanese Tokkaihei No. 2-276691, No. 8-319054, and Japanese Tokkohei No. 5-41991.
A bookbinding apparatus disclosed in Japanese Tokkaisho No. 60-183459 has a cover sheet supply apparatus, and after a group of copying sheets and a cover sheet are superimposed, a bookbinding finishing operation such as holing or stapling is conducted.
Japanese Tokkaihei No. 6-72064, No. 7-187479, and No. 8-192951 disclose a sheet finisher having a center stapling processing function.
The above-described finisher has the following problems.
(d) In a sheet finisher which can conduct both of edge stapling processing to staple a set of sheets by putting stapler pins into one or two portions in the vicinity of the side edge of the set of sheets, and center stapling processing to staple a set of sheets by putting stapler pins into a central portion in the conveyance direction of a set of sheets, the edge stapling processed set of sheets is delivered by a normally rotating delivery belt and a delivery roller pair which is normally rotated by being interlocked with the delivery belt, onto a movable delivery sheet tray provided outside the apparatus.
In the case where sheets on which edge stapling processing is not conducted, exist on the movable delivery sheet tray, when the delivery belt and the delivery roller pair are reversely rotated in order to convey a set of sheets which is center stapling-processed, to the next twice-folding process, the trailing edge of the sheet on the movable delivery sheet tray is wound into the apparatus by the reversely rotating delivery roller pair and reversely moved into the apparatus, thereby, a sheet damage is generated.
(e) In the sheet finisher which can conduct both of the edge Stapling processing and center stapling processing, the delivery means to deliver the set of sheets which is edge stapling-processed, onto the movable delivery sheet tray outside the apparatus is different from a conveyance means to convey the set of sheets which is center stapling-processed, to the next process, therefore, the apparatus is complicated. Further, the timing adjustment for each of the delivery means after the edge stapling processing and the conveyance means after the center stapling processing is also complicated.
(f) In the conventional sheet finisher, a drive source (motor, etc.) of a movable stopper member for a flat stapling mode and a drive source (motor, etc.) of a movable stopper member for the center stapling are separately provided, thereby, the production cost is increased.
(g) When a stepping motor is used for a drive source, because sometimes a phase shift is generated by the external force, it is necessary that an initializing operation is conducted before the start of the drive, to position the motor at a position at which the drive can be started. When one portion is operated being interlocked with another portion, it is necessary to limit the order of each initializing operation. When the order of them is mistaken, interference is generated among operation members, resulting in a failure of the apparatus. In order to prevent that, the driving system of the apparatus becomes complicated, which is a defect.
(h) The length of the sheet in its conveyance direction is different depending on the environmental temperature, cutting accuracy, one side or two-sided recording, etc. After the leading edge portions of the sheets having the difference in the length are defined as the reference, and sheets are arranged at the leading edge portion, when center stapling and center-folding are conducted, the trailing edge portions of the sheets are irregular due to the difference of the length of the sheet. In the case where irregular trailing edge portions of this twice-folded processed set of sheets are cut by a cutter, or the like, when sheets are cut by making the edge portion of the outermost sheet as the reference, if the a sheet whose overall length is short, exists inside the set of sheets, an irregular portion remains after cutting, thereby, the finished appearance of the set of sheets is spoiled.
(i) In the case where a movable stopper member for the twice-folding is moved corresponding to the sheet size, stopped at a predetermined position, and the leading edge portion of the conveying set of sheets is positioned, when a stepping motor is used as a drive source, the movable stopper member is moved by the impulsive force from the leading edge portion of the conveying set of sheets. When the movable stopper member is moved and shifted from the predetermined position, the twice-folding portion at the center of the sheet is shifted, and the leading edge portion of the set of the sheets does not coincide with the trailing edge of the set of sheets, thereby, the finished appearance of the set of sheets is spoiled.
(j) In the conventional sheet finisher, a width arrangement means to arrange the sheet width direction perpendicular to the sheet conveyance direction is arranged on only the upstream side of the staple means in the sheet conveyance direction. When the edge stapling processing is conducted, the width arrangement means is located in the vicinity of the upstream side of the staple means, therefore, there is no problem. When the center stapling processing is conducted, the leading edge portion of the set of sheets is positioned by a positioning stopper which is arranged on far downstream side from the width arrangement means. In the vicinity of the positioning stopper, there is no limitation in the sheet width direction, therefore, the width direction of the sheet is not arranged in order. When the center stapling processing or center folding processing is conducted on this irregular set of sheets, the quality of external appearance of a finished booklet is decreased.
(k) A positioning means to arrange the leading edge portion in the sheet conveyance direction (sheet size stopper) is formed relatively small in the size, however, the width arrangement means to regulate the sheet width in the perpendicular direction to the sheet conveyance direction (side guide) is formed long in the sheet conveyance direction in order to prevent the slanting movement of the sheet, and the driving means is complicated, and a large area is necessary. When this width arrangement means is arranged on the upper side of the sheet conveyance surface, a gap above a sheet placement portion is small, and therefore, when a sheet conveyance failure (jam) is generated in the vicinity of the sheet placement portion, it is difficult to visually check the jammed sheet and take out it.
(l) In the conventional sheet finisher, the sheet placement board, staple means, sheet width arrangement means, and sheet leading edge portion positioning means to conduct the edge stapling processing and center stapling processing, are directly equipped in the sheet finisher main body. Accordingly, when a jam, failures-of component members, stapling failure, or the like, is generated in the sheet finisher, or when replenishment of stapler pins or the maintenance operation is conducted, it is necessary to conduct operations, adjustment, or the similar operations, in the sheet finisher, therefore, the working property is not good.
An object of the present invention is to provide a sheet finisher to solve the above-described problems (a)-(l) in the conventional sheet finisher, and to structure an upper and lower portion separation type stapler which conducts the edge stapling processing, center stapling processing, or slant end stapling processing on sheets delivered from an image forming apparatus, by a simple structure. Further object of the present invention is to provide a sheet finisher by which the phases of an upper mechanism driven portion and a lower mechanism driving portion of the upper and lower portion separation type stapler can be correctly maintained.
(1) A sheet finisher to solve the above-described problems is structured as follows. In a sheet finisher having a staple means for conducting edge stapling processing to put stapler pins into an edge portion of sheets, and center stapling processing to put stapler pins at a central portion of sheets, the stapling means is formed into a two-piece structure in which a driving side mechanism to put stapler pins into sheets is arranged on the lower side of a sheet conveyance path and a driven side mechanism to clinch stapler pins is arranged on the upper side of the sheet conveyance path; a plural sets of the two-piece structure staple means are arranged in the direction perpendicular to the sheet conveyance direction; the staple means can be moved in the direction perpendicular to the sheet conveyance direction by a driving means having only one driving source; at least one set of the staple means is driven so as to be rotated by a predetermined angle with respect to the direction perpendicular to the sheet conveyance direction; and the rotation center of the staple means almost coincides with the center of the stapler pin.
(2) In a sheet finisher having a conveyance means for successively receiving and conveying image-formed sheets conveyed from an image forming apparatus; a stacking means for positioning and stacking the received sheets; and a staple means for stapling the stacked sheets on the stacking means, the sheet finisher has: the staple means which can conduct both of edge stapling processing to staple one end of the sheet, and center stapling processing to staple the central portion of the sheets in the conveyance direction of the sheets, and which is two-piece structured so that the sheet can pass through the staple means; a movable stopper member for the center stapling processing which moves to a predetermined position in the conveyance direction of the sheets corresponding to the sheet size stacked on the stacking means and positions the sheet end; and a movable stopper for the edge stapling processing which is interlocked with the movement of the movable stopper member for the center stapling processing, and shuts off the sheet conveyance path, and positions the sheet ends so that the edge stapling processing can be conducted, and which is withdrawn from the sheet conveyance path so that the sheets to be center stapling processed can pass through the staple means.
(3) In the sheet finisher described in Item (2), the sheet finisher is structured as follows: when the movable stopper for the center stapling processing is positioned at a home position, the movable stopper member for the edge stapling processing is set at a sheet leading edge positioning position to shut off the sheet conveyance path; and when a power source of the sheet finisher is turned on, initialization of a stop position of the staple means is conducted after an initialization operation of the center stapling stopper unit.
(4) In the sheet finisher described in Item (2), the sheet finisher has a sheet positioning means for enabling a position of the movable stopper member for the center stapling processing to be adjusted corresponding to the length in the conveyance direction of the sheet conveying into the sheet finisher.
(5) In the sheet finisher described in Item (2), the sheet finisher has: the folding means for making the sheet twice-folded; a movable stopper member for folding means to move the sheet conveyed onto the stack board of the folding means to a predetermined position in the sheet conveyance direction corresponding to the sheet size, and to position the leading edge of the sheet; and a measurement means for measuring the length in the sheet conveyance direction of the sheet conveying into the sheet finisher, wherein the sheet positioning means of the movable stopper member for the center stapling processing and the sheet positioning means of the movable stopper member for the folding means determine the stop position on the basis of the minimum length in the sheet conveyance direction according to the measured value of the sheet length in the sheet conveyance direction by the measurement means, during the sheet post processing operation to produce one booklet.
(6) In the sheet finisher described in Item (5), the sheet finisher has: a stepping motor driving means for driving the movable stopper member to be movable; a control means for controlling the stepping motor driving means; and a detection means for detecting the entry of the sheet into the movable stopper member of the folding means, wherein the stepping motor driving means is controlled by the detection signal of the detecting means, and the rotation of the stepping motor driving means is stopped and fixed just before the leading edge portion of the sheet comes into contact with the movable stopper member.
(7) In the sheet finisher which can conduct both of the edge stapling processing to staple one end of sheets, and the center stapling processing to staple the central portion of the sheets in the conveyance direction, the sheet finisher has: a vertically movable sheet delivery tray which receives edge stapling processed sheets, or sheets which are not edge stapling processed; a sheet stacking portion on which sheets to be edge stapling processed and sheets to be center stapling processed are stacked; a delivery roller pair to nip the sheets and deliver them onto the movable delivery sheet tray; and a rotatable delivery means having a delivery member which comes into contact with the end portion of a set of sheets stacked on the sheet stacking portion, wherein, after the edge stapling processing, the delivery means is normally rotated and the delivery member presses the trailing edge portion of a set of processed sheets and conveys the set to the delivery roller pair, and the set of sheets are nipped by the roller pair and delivered onto the movable delivery tray; and after the center stapling processing, the delivery means is reversely rotated, and the delivery member presses the other end portion of the set of processed sheets and conveys the set to the next process, and before the reversal rotation of the delivery means, the movable delivery sheet tray on which delivered sheets are stacked, is lowered from a predetermined position.
(8) In the sheet finisher described in Item (7), the delivery member is switched to each of the standby position at the time of the edge stapling processing and the standby position at the time of the center stapling processing, and arranged at that position.
(9) In the sheet finisher which can conduct both of the edge stapling processing to staple one end of sheets, and the center stapling processing to staple the central portion of the sheets in the conveyance direction, and has a staple means which is divided-structured through the sheet path on which the sheet can pass at the time of the center stapling processing, an upper stream side width arrangement means and a downstream side width arrangement means for arranging the sheet width in the direction perpendicular to the sheet conveyance direction are arranged at each of the upper stream side and the down stream side in the sheet conveyance direction of the staple means.
(10) In the sheet finisher described in Item (9), a driving portion of a sheet end portion positioning means for regulating the sheet end portion in the sheet conveyance direction at the time of the edge stapling processing and the center stapling processing, is arranged on the upper side of the sheet conveyance surface, and a driving portion of the width arrangement means for regulating the sheet width in the direction perpendicular to the sheet conveyance direction, is arranged on the lower side of the sheet conveyance surface.
(11) In the sheet finisher described in Item (9), at least one set of staple means which is structured by being divided into upper and lower portions through the sheet path on which the sheet can pass at the time of the center stapling processing; the width arrangement means for arranging the sheets in the width direction perpendicular to the sheet conveyance direction; the sheet end portion positioning means to regulate the sheet end portion in the sheet conveyance direction; and the sheet stacking portion on which the sets of sheets to be subjected to the end stapling processing and center stapling processing are stacked, are structured into a unit, and the unit is structured so as to be drawn from the sheet finisher main body in the direction perpendicular to the sheet conveyance direction.